Resonantly Enhanced Electromigration Forces for Adsorbates on Graphene

ORAL

Abstract

We investigate the electromigration forces for weakly bonded adsorbates on graphene by using density-functional based calculations. We find that the nature of electromigration forces on an adsorbate critically depends on the energy level alignment between the adsorbate state and the Fermi level of the graphene. For a resonant adsorbate, whose frontier orbitals lie close to the Fermi level, the electromigration force is dominated by the electron wind force that is strongly enhanced along the electron flow direction, irrespective of the sign of the adsorbate charge. For a nonresonant adsorbate, the electromigration force is essentially the direct force that depends on the adsorbate charge. We also show that the magnitude of electromigration forces can be continuously tunable through electrostatic gating for resonant adsorbates. Our results provide new insight for understanding and controlling how nanoscale objects behave in or on host materials.

*We thank Michael F. Crommie, Hsin-Zon Tsai, and Franklin Liou for helpful discussions. This work was supported primarily by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the US Department of Energy under Contract No. DE-AC02-05-CH11231, within the Theory of Materials program (KC2301). Further support was provided by the NSF Grant No. DMR-1926004. Computational resources used were Cori at National Energy Research Scientific Computing Center (NERSC), which is supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05-CH11231, Stampede2 at the Texas Advanced Computing Center (TACC) through Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation (NSF) under Grant No. ACI-1053575, Frontera at TACC, which is supported by NSF Grant No. OAC-1818253, and Bridges-2 at the Pittsburgh Supercomputing Center (PSC), which is supported by NSF Award Number ACI-1928147.

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Presenters

  • Young Woo Choi

    • University of California, Berkeley

Authors

  • Young Woo Choi

    • University of California, Berkeley

  • Marvin L Cohen

    • University of California, Berkeley